The present invention relates to a bundling apparatus for collectively bundling objects to be bundled stacked in a pile, and more specifically, to a bundling apparatus in which a band material coated on one side with a thermally fusible material is wound around a stack of objects to be bundled and then thermally welded to bundle the objects.
A prior art bundling apparatus of this type is provided with a bundler which includes a pair of endless belts facing each other. In operation, objects to be bundled, e.g., sheets in a pile, are first fed and held with pressure between the pair of endless belts of the bundler. Meanwhile, a thermal adhesive tape (coated on one side with a thermally fusible material) supplied from a reel is wound around the retained stack of sheets, being delivered as the bundler rotates. One end portion of the wound tape is superposed on the other portion of the wound tape and bonded with heat and pressure by a heater block. Thus, the stack of sheets is bundled. In thermally bonding the thermal adhesive tape wound around the stack of the sheets with the coated face inward, the fusible material melted by the heat of the heater block must be kept from sticking to the sheets. Accordingly, a heater pad is inserted between the stack of sheets and that portion of the thermal adhesive tape to be bonded so that the tape is prevented from sticking to the stack of sheets.
In a continuous bundling operation, however, the heater pad will be heated by heat transfered from the heater block. As a result, the thermal adhesive tape will sometimes stick to the heater pad, possibly causing defective bundling or even disabling the apparatus.